19-2349; Rev 3; 12/05 Low-Cost, Power-On Reset and Watchdog Controllers The MAX698/MAX699 monitor the +5V supply in microprocessor (µP) and digital systems. They supply a RESET pulse of at least 140ms duration on power-up, power-down, and during low-voltage brownout conditions. Circuit reliability is increased at reduced cost by eliminating all external components and adjustments. The MAX699 includes all features of the MAX698, but also provides a watchdog input to monitor microprocessor activity. The RESET output goes low if the watchdog input (WDI) is not toggled within 1 second. The watchdog feature can be disabled by leaving WDI open. Both parts are supplied in 8-lead PDIP and 16-lead 0.3in wide small outline (SO) packages and are specified from 0°C to +70°C for C grade devices and -40°C to +85°C for E devices. The SO versions, with more pins than the 8-lead PDIP, have additional outputs not available in DIP packages. These are RESET (without inversion) and watchdog output (WDO). Applications Features ♦ Precision Voltage Monitor ♦ Power-OK/Reset Time Delay ♦ Watchdog Timer ♦ Minimum Component Count Ordering Information PART* TEMP RANGE PIN-PACKAGE MAX698CPA 0°C to +70°C 8 PDIP MAX698CWE 0°C to +70°C 16 Wide SO MAX698EPA -40°C to +85°C 8 PDIP MAX698EWE -40°C to +85°C 16 Wide SO MAX699CPA 0°C to +70°C 8 PDIP MAX699CWE 0°C to +70°C 16 Wide SO MAX699EPA -40°C to +85°C 8 PDIP MAX699EWE -40°C to +85°C 16 Wide SO Computers *Devices are available in both leaded and lead-free packag- Controllers ing. Specify lead free by adding the + symbol at the end of the part number when ordering. Intelligent Instruments Automotive Systems Pin Configuration Critical µP Power Monitoring TOP VIEW Typical Operating Circuit +5V VCC 1 VCC 2 8 GND 7 RESET MAX698 MAX699* GND 3 6 N.C. (WDI)* GND 4 5 N.C. +5V DIP 1 2 VCC GND VCC RESET 8 7 MAX698 6 3 GND N.C. GND N.C. 5 4 TO µP RESET INPUT GND 1 16 RESET VCC 2 15 RESET VCC 3 14 N.C. (WDO)* MAX698 MAX699* GND 4 13 N.C. N.C. 5 12 N.C. N.C. 6 11 N.C. (WDI)* N.C. 7 10 N.C. N.C. 8 9 GND * PIN LABELS IN ( ) ARE FOR MAX699 ONLY SO ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX698/MAX699 General Description MAX698/MAX699 Low-Cost, Power-On Reset and Watchdog Controllers ABSOLUTE MAXIMUM RATINGS VCC ........................................................................-0.3V to +6.0V Input Voltage (with respect to GND) WDI, WDO, RESET, RESET ..…………………………-0.3V to VCC Operating Temperature Range C Suffix………………………………………………0°C to +70°C E Suffix ......……………………………………….-40°C to +85°C Rate of Rise, VCC .................………………………………100V/µs Power Dissipation (TA = +70°C) 8-Pin PDIP (derated 5mW/°C above +70°C).....………400mW 16-Pin SO (derated 7mW/°C above +70°C) ................600mW Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = +5V, TA = +25°C, unless otherwise noted.) PARAMETER Operating Voltage Range MIN 3.0 TYP TA = full CONDITIONS MAX 5.5 UNITS V 5 mA Power-Up Reset Deassertion TA = full 4.50 4.65 4.75 V Power-Up Reset Assertion TA = full 4.4 Supply Current Hysteresis Reset Output Pulse Width 140 Output low ISINK = 1.6mA, VCC = 4.4V Output high ISOURCE = 1µA, VCC = 5V RESET OUTPUT (SO Package Only) Output low ISINK = 1.6mA, VCC = 5V Output high ISOURCE = 1µA, VCC = 4.4V WDO Output (MAX699 SO Package Only) Output low ISINK = 1.6mA, VCC = 5V Output high ISOURCE = 1µA, VCC = 4.4V RESET OUTPUT (Open Drain) 0.4 3.5 0.4 3.5 MAX699 Minimum WDI Input Pulse Width 200 MAX699 WDI Input Current 2 1.6 Logic-high 2.25 0.8 3.8 20 -50 ms V V V s ns Locic-low WDI = VCC WDI = 0V 500 0.4 1.00 VCC = +5V mV 3.5 MAX699 Watchdog Timeout Period MAX699 WDI Input Threshold V 40 -15 _______________________________________________________________________________________ 50 V µA Low-Cost, Power-On Reset and Watchdog Controllers PIN NAME FUNCTION SO PDIP 1, 4, 9 3, 4, 8 GND Chip Power Ground 2, 3 1, 2 VCC +5V Sense Input and MAX698/MAX699 Chip Power 5–8, 10–14 5, 6 N.C. No Connection 10 6 WDI (MAX699 Only) (MAX699 Only.) A three-level input. If WDI remains high or low for more than the watchdog timeout period, RESET pulses low (WDO also goes low on the MAX699 SO package). If WDI is unconnected, the watchdog circuit is disabled. (MAX699 Only.) Goes low when WDI remains high or low for more than the watchdog timeout period. WDO is set high at the next WDI transition. If WDI is unconnected or at midsupply, WDO remains high. WDO also remains high when VCC falls below 4.4V. 14 — WDO (MAX699 Only) 15 7 RESET Goes low when VCC falls below internally set threshold (see the Electrical Characteristics table). 16 — RESET Goes high when VCC falls below internally set threshold. WATCHDOG TIMER WDI* WDO* RESET TIMER RESET VCC RESET* VCC POWER-ON RESET 4.65V GND MAX698 MAX699 *WDI ON MAX699 ONLY RESET ON SO PACKAGE ONLY WDO ON SO MAX699 ONLY Figure 1. Block Diagram _______________________________________________________________________________________ 3 MAX698/MAX699 Pin Description MAX698/MAX699 Low-Cost, Power-On Reset and Watchdog Controllers Package Information For the latest package outline information, go to www.maxim-ic.com/packages. Chip Topography Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 4 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2005 Maxim Integrated Products Campillo Printed USA is a registered trademark of Maxim Integrated Products, Inc.